DNA End-Joining Catalyzed by Human Cell-Free Extracts
Abstract
Mammalian cells defective in DNA end-joining are highly sensitive to ionizing radiation and are immunodeficient because of a failure to complete V(D)J recombination. By using cell-free extracts prepared from human lymphoblastoid cell lines, an in vitro system for end-joining has been developed. Intermolecular ligation was found to be accurate and to depend on DNA ligase IV/Xrcc4 and requires Ku70, Ku86, and DNA-PKcs, the three subunits of the DNA-activated protein kinase DNA-PK. Because these activities are involved in the cellular resistance to x-irradiation and V(D)J recombination, the development of this in vitro system provides an important advance in the study of the mechanism of DNA end-joining in human cells.
- Publication:
-
Proceedings of the National Academy of Science
- Pub Date:
- November 1998
- DOI:
- 10.1073/pnas.95.24.14066
- Bibcode:
- 1998PNAS...9514066B